‘Tis the season to think twice about proper barn ventilation to protect your pigs and to promote energy efficiency.
“Ventilation is not always top of mind for many producers heading into winter,” says Austin Zimmerman, sales engineer for AP. “But it’s a crucial time to assure good air quality and avoid any pockets of gas.”
Ventilation systems control the air quality and temperature within hog buildings which impact pig health and performance, explains Sam Holst, DVM, with Swine Vet Center. Not only does poor ventilation increase disease opportunities, but it also reduces growth rate by creating a barn environment high in humidity and excess gasses.
“Many ventilation mistakes are often the result of efforts to save utility costs. An understanding of fundamental ventilation concepts along with routine monitoring to ensure ventilation systems are working properly will help set up a barn environment that both optimizes pig health and performance while keeping utility costs in-line,” Holst says.
Here are five tips to consider as winter approaches.
1. Ensure correct minimum ventilation settings.
Minimum ventilation is the amount of fresh air needed to be brought into the barn to control humidity and gas contaminants such as carbon dioxide and ammonia. This is particularly important during cold weather as ventilation systems will spend much of the winter season operating in minimum ventilation mode.
“Accuracy with minimum ventilation settings is crucial as over-ventilating will inflate utility costs (propane and electricity) while under-ventilating will produce an environment detrimental to pig health and performance,” Holst says.
Minimum ventilation needs are calculated based on the number and size of pigs in a barn. Controller settings to achieve the needed minimum ventilation are dependent on the number and size of fans on stage one. Holst says it’s critical to take the time to calculate the minimum ventilation rate needed rather than set minimum ventilation fans at an arbitrary minimum speed. He recommends using reference charts for fan CFM (cubic feet per minute) output and required CFMs per pig for these calculations.
2. Check heater settings.
As furnace use increases with colder weather, correct heater settings are key to achieving consistent room temperatures and limiting propane waste. A common problem found in barns are furnaces that shut off too close to the setpoint temperature, Holst says. When this occurs, room temperature rises even after the furnace shuts off as it takes some time for the heated air to circulate and for the probes to detect the room temperature increase.
“If the heater is programmed to shut off too close to set point, the room temperature will rise above the set point causing minimum ventilation fans to ramp up and exhaust the heated air to cool the room – essentially blowing recently burned propane right out the exhaust fans,” Holst says. “Correct heater settings can reduce propane use by several gallons per heater per day resulting in significant energy savings.”
An effective way to fine-tune furnace settings is to make note of the current settings and observe the room temperature as it cycles through a heater on and off run, Holst offers. Ideally, after the heater shuts off the room temperature should rise to just below the set point without going over. If the room temperature rises above set point, adjust heater settings so that the heater shuts off further below set point, he says.
3. Check temperature probes.
Ventilation controllers rely entirely on temperature data received from multiple probes located throughout the pig space, Holst explains.
“If probes are placed incorrectly, the controller will receive inaccurate readings resulting in incorrect controller operation and barn environment,” he says.
Recommended height and location of temperature probes varies by barn type and stage of production. Adjust probe height between nursery and finisher stages in wean-to-finish barns. Probes should be positioned away from ceiling inlets and heaters to avoid artificial fluctuations in temperature from cold or hot air, Holst advises.
Source: Sam Holst, Swine Vet Center
“Ensure that all temperature sensors are working correctly,” Zimmerman adds. “If one sensor is not working, replacing it is optimal. Otherwise, simply remove it, as the remaining sensors can still function.”
4. Clean and inspect exhaust fans and heaters.
Don’t forget to clean exhaust fans. Even an 1/8 inch of dust or dirt can reduce fan efficiency by up to 40%, Holst says.
“Inspect fans to confirm they are in good working condition and that fan belts have the proper tension. Also, confirm that fan shutters are in good working condition,” Zimmerman adds.
Use compressed air or a leaf blower tool to blow dust and debris out of heaters. This will help promote efficient as well as safe operation of the units, Zimmerman says. Check the ignitor, sail switch and flame sensor to make sure they are not covered with carbon or dust. Carbon can build up as a byproduct of the burner, he adds.
5. Check inlet operation.
Inspect inlets for any blockage, damage or wear that may prevent normal air flow.
“Be sure inlet mechanisms are greased and respond correctly to the control inputs,” Zimmerman says. “If not, an inlet calibration or reset may be necessary.”
Bonus Tip: Cover curtains with bubble wrap or plastic.
In addition, Zimmerman encourages producers to check barn curtains to make sure they are in good physical condition and that the curtains reset to their open or closed position to properly calibrate the curtain machine.
One way to reduce drafts and heat loss is to cover curtains, Holst recommends.
“Too much cold air entering the barn during winter can cause excessive use of heaters, wasting propane,” Zimmerman says.
When In Doubt, Call Your Veterinarian
Need help identifying potential ventilation problems? Veterinarians can help producers review ventilation settings and identify potential areas of concern, Holst says.
“Utilizing meters to measure components that impact air quality (oxygen, carbon dioxide, ammonia) and data loggers that collect temperature and humidity data over extended periods of time can be helpful to diagnose ventilation issues,” he adds.
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